The objective of this research is to determine the role that metabolic N-oxidation plays in the mechanism by which certain aromatic amines induce tumor formation in the urinary bladder of the dog. Experimental evidence indicates that the N-hydroxylated metabolites of the carcinogenic aromatic amines and amides as well as their esters react with DNA. In order to study the role of DNA binding in the induction of bladder cancer we are investigating the feasibility of employing immunochemical techniques to detect as well as characterize those modifications of the DNA of dog bladder mucosal epithelium that are induced in vivo by the oral administration of 2-naphthylamine, 4-biphenylamine and 2-fluorenylamine and by the instillation into the bladder of their N-arylhydroxylamine and nitroso derivatives.